Mill



May .17, w32. F. E. MARCY n 1,858,594'

' MILL Filed April 3o, 192s Patented May `17, 1932 FRANK E. MAR-CY, OF SAN DIEGO, CALIFORNIA MILL Application med pra 3o,

My invention relates to an improvement in mills of the type wherein balls, rods, pebbles or other reducing medium are confined within a. drum with the material to be reduced, the

'51 rotation of the drum and its contained load on its bearings reducing the material by impact and attrition. f

One of the objects of the present invention is the provision of a mill of the type above generally referred to in which a construction is employed which will facilitate unloading or emptying of the mill.

Another object of thepresent invention is to provide a mill of the type above referred to in which a grate is provided adjacent the discharge endv thereof, means being provided for introducing Water into the mill drum adjacent the grate so as to flush the lines, i. e.,

material which has been reduced to the de- 80 sired degree of neness, through the grate,

thereby reducing the amount of water required to be introduced with the load, and hence increasing the reducing action and efiiciency of the mill.

A still further object of the invention lis the provision of a shell or wall liner which is of improved and novel construction.

I am aware that it has been proposed prior to the present invention to provide mills with 80 a shell manhole but in such structures it is customary toy protect the cover withv a liner secured to the cover only. This is unsatisfactory, however, in that the shell liner must be cut to accommodate this cover, and diffiliner securely attached to the cover.

The present construction provides a mill in which the'necessity of a separate liner for the manhole cover is eliminated, the shell liner itself being extended across and protecting the cover therefor. In emptying the mill it is merely necessary to enter the interior of the mill7 remove the shell liner covering the manhole opening, and then to rotate the mill for a partial turn to dump the load.

The present invention provides also a structure in which provision is made for feeding water to the interior of the mill adjacent the inner face of the grate to sluicc the fines therethrough, thereby increasing the disculty has been experienced in holding thel 1928. Serial No. 273,803.

charge of reduced material and reducing the quantity of water heretoforenecessarily fed to the mill with the material to be reduced. A reduction in the amount of water fed to the mill necessarily reduces the cushioning 'effect of the pulp on the reducing mediumvand,

increases the reducing action accordingly.

In the accompanying drawings, Fig. 1 shows in longitudinal sectional elevation a mill embodying m'y invention;

F ig. 2 is a section transverse of Fig. l and facing the discharge end of the mill; .and

Fig. 3 shows in perspective a section of the improved shell liner employed. p

Referring to the drawings in detail, l desig-l nates the shell or drum of the mill. This drum which is appreciably greater in length than diameter is provided with feed head 2, discharge' head 3, feed ltrunnion 4 and di`scharge trunnion 5. The trunnions are mounted in trunnion bearings 6 and 7, respectively. The milldrum may be rotated by a drive of conventional design well known to those skilled in this art and hence the samehas not beenl illustrated. The feed head is provided with manholes 8 and covers 9 therefor bolted on in the usual way.

The shell or wall of the drum l is provided with sectional wall liners 10, one of Which v has been illustrated in perspective in Fig. 3.

These liners are of anew construction and held in place in the mill by bolts 11.

As will be seien from Fi s. 2 and 3 the shcll or wall liners are of un ulating or wave .form not only on the inner or Wearing surface or face l2 but on the outer or underside 18Y as well, that is to say on the side adjacent the shell or wall of the drum. Preferably the undulations on the underside of the liner sections are offset slightly with respect to the undulations on the wearing surface so as to compensate for thc wear on the liner due to the action of the mill load ,954

thereon. For instance an inspection of Fig. 2 will show that the depressions let on the wearing surface l2 are slightly inv advance of the. corresponding depressions l5 on the underside of the liner, the mill, it is assumed,

rotating in the direction of the arrow on Fig. 2. I

The edges of the wall liner sections are beveled as indicated at 16 and 17 so that the 5 liner sections may be readily placed or set shown at J4 to the inner side of the grate,

thereby7 providing means adjacent the grate for introducing Water into the mill at the inner face ot' the grate to sluice the fines therethrough.

In operation the mill is rotated in the trimnion bearings 6 and 7, material being fed into the mill through the feed trunnion 4. As the mill rotated in the direction of the arrow on Fig. 2 for instance the load including the reducing medium is carried upwardly finally tumbling and cascading toward the bottomeof the mill drum, to effect reduction of the material by impact and attrition. The Wave formation of the liners assists in this upward movement, yas will be understood. As the mill rotates' the material is constantly worked toward the grate sectors 18 and the fines, i. e.,

` the material which has been suiliciently re.

duced, works through the grate, is elevated by the litters 17 and discharged from the mill through the trunnion 5. To promote the passage ot the lines through the grate sectors Water may be introduced to the interior of the mill adjacent the inner face of the grates While the mill is in operation through the pipe :23, this Water sluicing the fines through the grates. Thispermits of operation with the introduction of less Water with the load than is customary in present'practice, thereby reducing the amount of pulp in the mill and to the same degree reducing the cushioning eil'eet of this pulp, and permitting the reducing medium to act with that much more etliciency upon the material being reduced. As a result, therefore, the eflicieney of the mill will be increased.

The liners by reason of their wave formation on both faces may be rolled instead of cast, and by offsetting these formations, as above explained, wear on the grinding surface of the liner is compensated for and hence the life of the liner is prolonged to that extent, and renewal of the liner sections is required less frequently than with liner sections heretofore employed.

It will be apparent also that I have provided a mill structure in which the shell lin ers extend across the manhole opening, thus eliminating the trouble experienced hereto fore with that type of mill in which the shell manhole cover has been lined.

lVhat I claim is:

1. A mill comprising a drum, the shell of which is provided with a manhole opening, and a liner for the drum shell overlying said manhole opening. Y

2. A mill comprising a drum, the .shell of which is provided With a manhole opening sectional liners for said shell, at least one ot said `sections extending across said manhole opening.

8. A mill comprising a shell, a feed head and a discharge head, one of said heads and the shell being provided with a manhole opening, and a liner for said shell extending -across the manhole opening in the shell.

L1. A rolled steel liner for mills having a wave or undulating surface on its Wearing face leading or offset toa Wave or undulating surface provided o n the opposite face of the liner, said liner being of the same cross section throughout its length.

5. A rolled steel liner for mill drum shells, comprising liner sections extending length- Wise of the drum, the adjacent edges of the liner sections being beveled to facilitate placement and removal of the sections, each section being provided with wave or undulating surfaces on its wearing face and its inner face,

the formation on the Wearing' face leading the formation on the inner face.

6. The combination of a mill drum, flat grate surfaces adjacent the discharge end of said drum, a cone centrally located within said drum, said grate sectors being so assembled about said cone as to lie in the one plane and extend radially of the mill drum, and a Water pipe passing through said cone from the exterior of the mill and terminating at such a point with reference to the inner conical face of the cone and the inner face of the grate sectors that water issuing from said pipe will, be directed upon the inner faces of the grate'sc-tors.

This specification signed this 2l day of` April, 1928.

FRANK E. MARCY.

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